Binaural Recording Bodycams & the Assassination of JFK

No matter where you stand on the issue of bodycams, there is one thing we can probably all agree on: video footage only tells a fraction of the story. A clear audio recording often proves essential because, when used for investigative purposes, images don’t always speak for themselves. Take Abraham Zapruder’s recording of the JFK assassination — a silent 26-second film that has spawned a seemingly infinite number of contradictory theories about the direction of sound. Depending on how you look at it, Zapruder’s film proves either that Oswald acted alone (as the Warren Commission concluded) or that there must’ve been a second gunman on the grassy knoll (back, and to the left…back, and to the left).

When Zapruder’s film was shown on TV for the first time in 1975, it didn’t reveal the truth; rather, it shattered the truth into millions of pieces. The shocked audience watching at home had just lived through Watergate and now they had all sorts of new questions about JFK, which swiftly led to the formation of the House Select Committee on Assassinations. After a two-year re-investigation, the Committee was just about ready to conclude that Oswald had indeed acted alone — they even had a draft of the final report — when a crucial new piece of evidence suddenly emerged: an audio recording.

The committee members were analyzing radio transmissions from the Dallas Police Department when they heard what they thought were four gunshots — not three, per the Warren Report. The audio clip was captured by a Dallas police officer whose microphone had been in the “on” position. Based on a study of acoustical impulse patterns, the Committee determined that, at the time when the first shot was fired, the officer was on a motorcycle traveling approximately “120-138 feet” behind the presidential limousine. Their conclusion: “Scientific acoustical evidence establishes a high probability that at least two gunmen fired at the President.”

There was just one problem: the sounds in the recording didn’t match up with the experience of H.B. McClain. The Committee used amateur film footage (not Zapruder’s) to identify McClain as the motorcycle officer. When the limousine picked up speed, McClain followed it all the way to the hospital, sirens blaring all around him. But, in the recording, you don’t hear sirens until two minutes after the supposed shots are fired. Subsequent acoustical research undermined the Committee’s conclusion, and a more recent study has persuasively placed the origin of the audio recording two miles away from Dealey Plaza. The gunshots? Just pops on the tape.

All of this contradictory evidence nonetheless points to the fact that when it comes to sussing out what really happened, audio is potentially just as important as video. And we’ve come a long way since the dictaphone. If McClain had been wearing, say, wireless 3D audio headphones with binaural microphones embedded in each earbud, the recording of what he’d heard and his precise location when he’d heard it would’ve been perfectly in sync.

A binaural recording captures sound as you actually hear it — from various directions and distances at once. It is far superior to, and much less manipulable than, the mono audio captured by today’s bodycams. When you play back a binaural recording using any ordinary pair of stereo headphones, you can locate sound in space from the same exact position where the recording was made. In the historically impossible case of McClain, a binaural recording likely would’ve revealed the direction from which the gun (or guns) had been fired. Bluetooth 3D headphones didn’t exist back then, but they do now. So why aren’t citizens and police departments alike clamoring for binaural audio bodycams?

It’s not for a lack of interest in audio as an investigative tool. In fact, one of today’s hottestemergingfields among criminal justice researchers is forensic gunshot acoustics. Investigators are now analyzing soundwaves to determine the specific type of gun and ammunition that were used. Thanks to the ubiquity of smartphones, investigators have access to many more amateur recordings than the House Select Committee on Assassinations did. When an incident occurs, we impulsively reach for our smartphones. We are all Zapruders now. But, as one amateur analyst of forensic gunshot acoustics has observed, “Amateur audio recordings are usually poor quality, with interference from voices, screams and echoes. Furthermore, the sound of the gunshot will depend on the position of the recorder relative to the shooter.”

And that position is crucially important when the recorder is a police officer. Forensic acoustics may enable us to determine the type of gun that was used, but it can’t re-create what it felt like to make a split-second decision under duress. Binaural audio would put you in that officer’s shoes, revealing the circumstances under which he or she acted, in ways that an image never could. Binaural audio isn’t just a powerful investigative tool — it also provides listeners with a pathway to empathy.

Bodycams are continuously on, but you need to press “play” in order to save a recording. As the Baltimore police officer who accidentally recorded himself planting drugs at a crime scene learned the hard way, bodycams save the last 30 seconds of footage before they’ve been manually activated. It’s a feature that accounts for the element of surprise: when suddenly faced with a dangerous situation, pressing “play” might not be the first thing on the officer’s mind. But those first thirty seconds are silent. The audio doesn’t kick in until “play” was pressed, thus potentially depriving investigators of crucial evidence. As we wrote in a previous post on protesters, who stand to benefit from binaural audio just as much as law enforcement: “In moments of conflict, as cameras face the ground, while their holders run from various oncoming threats or ISP access gets blocked from a possible mobile electromagnetic pulse — we still have our ears.”

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